Dr. Ira Warren, in his Family Physician, cautiously says, there is some reason to suppose that the time of impregnation governs the sex.

Should the puzzled reader ask me to give him a plausible explanation of the fact that so many witnesses can thus testify to their own similar experiences, and yet be deceived as to the truth, I must Confess that I give it up. It is the psychological riddle which has perplexed me from the outset far more than my subject of inquiry. The witnesses appear to be credible, and it is very difficult to believe that they are deliberate falsifiers, or that they are self-deluded as to the actual result of their experiments. But that they are wrong in their conclusions I promise to convince every candid reader.

The following extract from the National Live Stock Journal for August, 1874, is interesting, as a comment upon the above theory, with the additional element of the relative age of the parents; and the conclusion arrived at by a journal devoted to practical treeding and stock-raising is important:

"It has long been a study among breeders to control the sex of calves and colts, and many have been the theories advanced, and experiments made with reference to it. Coupling at certain stages of heat, and mating animals of certain ages, etc., have been resorted to, and about the time some one has made p his mind that he has discovered the true rule, events have transpired to show that he is mistaken. "Breeders have great faith in their power to develop, by mere breeding, any quality which they deem valuable, and it is not strange that they should Lave fallen back upon the fundamental idea and

sought to control the sex, as they do colour, milking qualities, speed, form, etc., by selecting sires and dams coming from families in which the desired sex predominates. But this theory, it seems, will not work with any more certainty than the other, and we suspect that there is a general average of both sexes produced; and that in the case of a mare or cow producing a greater number than the average of one sex, there is a tendency in the offspring to depart from it in the other direction-at least far enough to restore the equilibrium. If this is not so, the facts seem to show that the tendency to produce either one sex or the other is not a peculiarity which is transmissible, and that breeding for females does not promise a large measure of success. As to the reproductive power of females from dams far advanced in years, which, while it may or may not be sustained by the facts, is certainly worthy of investigation, we should be pleased to hear the experience of breeders upon this point."

It will be noted that practical experience here suggests the conclusions I have arrived at in the previous chapter, viz., that the sexes are produced equally, and that Nature tends to restore the equilibrium when any disturbance occurs.

And if the curious reader will inquire for himself of different breeders, he will find that one will very likely think well of this theory; a second will admit that at times he is almost led to believe there is something in it; while a third will express his contempt for the propagators of all such theories. This, in substance, has been my experience in consulting with breeders everywhere.

Upon the point in question, the testimony of Darwin—who made such a speciality of sex-ought to have great weight. In the revised edition of his Descent of Man he says: "The period of impreg

nation has been thought to be the efficient cause in determining the sex; but recent observations discountenance this belief."

In searching for this law of sex from a purely scientific standpoint, something worthy should be looked for, something in harmony with the simple and majestic laws of Nature, the grandeur and perfection of which are precisely in proportion to their simplicity and regularity.

The Thury-Napheys theory is at best but a surface theory; it does not pretend to give an explanation; it states facts, but lays down no rational bases for their support. Looking at it from the elevated point of view just mentioned, one is compelled to ask, Is it consistent to suppose that Nature has locked up this important principle in the ovulum of the female, decreeing that to-day, to-morrow, and next day, it shall be capable of producing one sex; after which, as if by some juggler's sleight, it shall be transformed into a germ of the other sex? Would it not be positive confusion if Nature has, as Dr. Hough maintains, given but six days, at most, per month, in which females can be conceived-and if in the last two or three of these they must be insufferable viragoes; and to the males has allotted as many more days-on the first three of which shall be produced specimens as much too effeminate as the preceding ones were too masculine ? Is it possible that Nature is thus constrained to inflict misery upon so

large a portion of the human family? Facts certainly do not corroborate this assumption by showing nearly one-half of the human race wrongly sexed. And further, how would this theory apply to twins, or to multiparous animals, where there may be several of either sex in one litter?

Now to all these difficulties the theory in question offers no reply, nor in my opinion can it ever offer a satisfactory one. It may, however, apply in the exceptional cases of females of delicate constitutions (see p. 177).

The next theory which I propose to consider may be termed the "Alternate Theory." It will at any rate show how easy it is to be misled by coincidences. It is simply this: That Nature makes all human ova either male or female, and supplies masculine one month, and feminine the next, thus preserving substantially a sexual balance. People are often successful in applying a theory such as this, or at least they believe so. Unfortunately, as there are but two sexes, by the law of probabilities just one half of the cases examined must be found in favour of almost any theory, while coincidence may increase the proportion in the limited number of cases examined to the extent of another 10 or 15 per cent. Now all facts that make for any hypothesis to which an inclination is shown, will impress the theorist much more strongly than those which clash with it; and hence, remembering the favourable cases better than those which are adverse, his conviction increases that the theory must be true. Were one to frame a theory that those born on Monday, Wednesday, and

Friday, are girls, and on other days boys, thousands of instances could at once be brought to sustain it.

I must now pass over many other theories which I have also examined and found to be fallacious, and come to an important and still very prevalent theory, which is as significant as it is popular, and which possesses three special features more or less blended by different authorities. It is important because it has so many positive facts which seem to favour it, and numerous writers, ancient and modern, have given it their support, declaring it to be "the one generally accepted." Hippocrates is claimed as the father of this theory. I dwell upon it, as it undoubtedly contains a good deal of truth, though the right explanation has been hitherto missed; and also because it will help to render my own theory more readily acceptable.

The

The three distinctive features of this theory may be designated: Comparative Vigour; Relative Age; and Nutrition. In other words, the parent who is physically the more vigorous at the time of conception gives his or her sex to the offspring. older parent, cæteris paribus, is assumed to be the more mature and vigorous, and hence imparts the sex. But without nutrition there is neither vigour nor life, and it is therefore considered safe to assume that the better nurtured will be the more vigorous, and thus determine the sex.

The eminent naturalist, Baron Cuvier, says: "Curious indeed are the experiments of M. Charles Girou de Buzareingues concerning the procreation of the sexes, both in the animal and vegetable king